首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2083篇
  免费   266篇
  国内免费   2篇
耳鼻咽喉   14篇
儿科学   75篇
妇产科学   96篇
基础医学   353篇
口腔科学   14篇
临床医学   246篇
内科学   361篇
皮肤病学   24篇
神经病学   193篇
特种医学   44篇
外科学   315篇
综合类   35篇
一般理论   1篇
预防医学   220篇
眼科学   26篇
药学   221篇
中国医学   1篇
肿瘤学   112篇
  2021年   21篇
  2018年   19篇
  2016年   21篇
  2015年   23篇
  2014年   51篇
  2013年   62篇
  2012年   82篇
  2011年   72篇
  2010年   44篇
  2009年   41篇
  2008年   87篇
  2007年   93篇
  2006年   75篇
  2005年   87篇
  2004年   78篇
  2003年   86篇
  2002年   89篇
  2001年   70篇
  2000年   61篇
  1999年   63篇
  1998年   31篇
  1997年   28篇
  1996年   33篇
  1995年   20篇
  1994年   32篇
  1993年   23篇
  1992年   51篇
  1991年   47篇
  1990年   45篇
  1989年   41篇
  1988年   39篇
  1987年   35篇
  1986年   39篇
  1985年   36篇
  1984年   38篇
  1983年   32篇
  1982年   28篇
  1981年   30篇
  1980年   28篇
  1979年   40篇
  1978年   25篇
  1977年   26篇
  1976年   34篇
  1975年   22篇
  1974年   29篇
  1973年   26篇
  1972年   35篇
  1971年   20篇
  1969年   18篇
  1968年   23篇
排序方式: 共有2351条查询结果,搜索用时 15 毫秒
91.
Myasthenic syndrome secondary to small cell lung cancer has been studied in five patients who achieved complete remission with chemotherapy. The relationship between response or relapse of the neoplasm to therapy and the activity of the myasthenic syndrome is variable. This inconsistent clinical correlation between the cancer and its paraneoplastic syndrome is examined in view of current data on the immunologic basis of myasthenic syndrome.  相似文献   
92.
Resident peritoneal macrophages, spleen macrophages and Kupffer cells isolated from normal CBA mice were treated with supernatants from spleen cells of normal or immunized mice, and cultured in the presence of heat-killed Listeria monocytogenes. The capacity of the macrophages, infected in vitro, to control the growth of Listeria was tested. In macrophages treated with supernatant from normal spleen cells, the organisms multiplied extensively during 24 h but in those treated with supernatant from immune spleen cells, growth was greatly inhibited. Macrophages isolated from mice irradiated with 8-9.5 Gy and treated with immune spleen cell supernatant, were as efficient or even more than those from unirradiated mice. The use of multispot slides proved to be a convenient and economical means of culturing and examining cells.  相似文献   
93.
Atrial myxomas are the most common benign tumors of the heart and are difficult to diagnose due to a wide variety of presenting symptoms. We present a patient with a five-year history of visual loss, vertigo, ataxia, tinnitus, and bone lesions that resolved after diagnosis and resection of an atrial myxoma. This case not only highlights an unusual presentation of atrial myxomas but also raises the question of whether atrial myxomas can produce paraneoplastic syndromes, including bone abnormalities.  相似文献   
94.
95.
Complement C3 activation is a characteristic finding in membranoproliferative GN (MPGN). This activation can be caused by immune complex deposition or an acquired or inherited defect in complement regulation. Deficiency of complement factor H has long been associated with MPGN. More recently, heterozygous genetic variants have been reported in sporadic cases of MPGN, although their functional significance has not been assessed. We describe a family with MPGN and acquired partial lipodystrophy. Although C3 nephritic factor was shown in family members with acquired partial lipodystrophy, it did not segregate with the renal phenotype. Genetic analysis revealed a novel heterozygous mutation in complement factor H (R83S) in addition to known risk polymorphisms carried by individuals with MPGN. Patients with MPGN had normal levels of factor H, and structural analysis of the mutant revealed only subtle alterations. However, functional analysis revealed profoundly reduced C3b binding, cofactor activity, and decay accelerating activity leading to loss of regulation of the alternative pathway. In summary, this family showed a confluence of common and rare functionally significant genetic risk factors causing disease. Data from our analysis of these factors highlight the role of the alternative pathway of complement in MPGN.  相似文献   
96.
We report here on a male diagnosed with tuberous sclerosis at 6 months of age. The child was treated with vigabatrin at age 6 months after an abnormal electroencephalogram but before onset of seizures. Vigabatrin was discontinued at age 13 months to avoid possible visual field defects. At 21 months, the child developed partial seizures with secondary generalization and infantile spasms. Standardized developmental assessments were performed at 12, 18, 24, 30, and 36 months of age. Cognitive and social development were normal until age 21 months and the onset of seizures. When assessed at 24 months, the child met criteria for autism and learning disability. This case indicates that the onset of epilepsy during an early stage in brain development can be associated with autistic regression and persistent developmental disorder. The case suggests the need to consider if possible visual field defects with vigabatrin outweigh the potentially deleterious effects of uncontrolled seizures.  相似文献   
97.
We tested functional activation for faces in patient D.F., who following acquired brain damage has a profound deficit in object recognition based on form (visual form agnosia) and also prosopagnosia that is undocumented to date. Functional imaging demonstrated that like our control observers, D.F. shows significantly more activation when passively viewing face compared to scene images in an area that is consistent with the fusiform face area (FFA) (p < 0.01). Control observers also show occipital face area (OFA) activation; however, whereas D.F.'s lesions appear to overlap the OFA bilaterally. We asked, given that D.F. shows FFA activation for faces, to what extent is she able to recognize faces? D.F. demonstrated a severe impairment in higher level face processing--she could not recognize face identity, gender or emotional expression. In contrast, she performed relatively normally on many face categorization tasks. D.F. can differentiate faces from non-faces given sufficient texture information and processing time, and she can do this is independent of color and illumination information. D.F. can use configural information for categorizing faces when they are presented in an upright but not a sideways orientation and given that she also cannot discriminate half-faces she may rely on a spatially symmetric feature arrangement. Faces appear to be a unique category, which she can classify even when she has no advance knowledge that she will be shown face images. Together, these imaging and behavioral data support the importance of the integrity of a complex network of regions for face identification, including more than just the FFA--in particular the OFA, a region believed to be associated with low-level processing.  相似文献   
98.
The aim of this longitudinal study was to assess the effect of rotating shift work on perceived sleep quality and sleep duration of nurses at Queen Elizabeth Central Hospital, Blantyre, Malawi. Twenty four female nurses were recruited at random from among personnel engaged in rotating shift work. The nurses worked a three-phase schedule: five day shifts (7.00 – 17.00) followed by three night shifts (17.00 – 7.00) and five days off. Controls were 22 female nurses who did not perform night duties. Sleep quality and duration was assessed using standardized and validated questionnaires on sleep duration and subjective sleep quality (SSQ). One-way analysis of variance revealed a significant effect of shift phase on total sleep duration (F = 36.8, d.f. = 8, P < 0.000) and perceived sleep quality (F = 8.81, d.f. = 3, P < 0.000). Night shift work was associated with reduction of sleep quality and duration. The after effects of night shifts persisted during days of the recovery period indicating accumulation of fatigue.  相似文献   
99.
TOPIC. This paper discusses some of the potential lessons to be learned from pilot studies, using a recently completed pilot study of exercise in outpatients with schizophrenia as a case example. CONCLUSIONS. Pilot studies are a source of important research and clinical information in the areas of recruitment barriers, attendance at study intervention sessions, monitoring procedures, physical sensations from study interventions, and additional outcomes. PRACTICE IMPLICATIONS. The author challenges psychiatric nurse clinicians to conduct and report the findings of pilot studies to enhance our knowledge and advance nursing science.  相似文献   
100.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号